Missing symbol in libGL

[wootletootle]

Hello all. I have a question about the nVidia libraries. I am trying to link an
application and get the following error message:

/usr/ansys_inc/v100/ansys/lib/linia32/libansys.so: undefined reference to `glPolygonOffsetEXT'

It turns out that this symbol is present in the default (Slack/RedHat) library
libGL (*) but when the nVidia drivers are installed it disappears. Is this a bug
in nVidia? What can I do to remedy the problem?

Thanks for your help,
Roger Young.

(*) and the application works prior to the nVidia installation

[AaronP]

This is a bug in the application. The glPolygonOffsetEXT function was part of the GL_EXT_polygon_offset extension, which was promoted to core OpenGL in OpenGL version 1.1. The application should either examine the extension string and use glXGetProcAddress, or link directly against glPolygonOffset (without the "EXT" suffix), thereby requiring OpenGL 1.1.

[wootletootle]

Thanks very much for your explanation
What if I can't recompile the application?
as in this case: it is the Ansys (finite element)
object file which I am trying to link to.
I can put in a bug report to Ansys, but from
experience it can take a while to get some
action. Is there anything I can do in the
meantime?

Cheers,
Roger.

[vnywn]

Link it with something like this:

#include <GL/gl.h>

void glPolygonOffsetEXT(float factor, float bias) {
glPolygonOffset(factor, bias);
}

[vnywn]

More eleborate instructions:

1. Save above in wrapper.c
2. gcc -fPIC -shared -o wrapper.so wrapper.c
3. run using: LD_PRELOAD=./wrapper.so [program name]

[wootletootle]

Thanks Vnywn, that worked!